Transfer mechanism



Feb. 4, 1964 D, F, BOWMAN 3,120,355

TRANSFER MECHANISM Filed Jan. 25, 1962 INVENTOR. 4Z .DHZ/A0 F 50W/174A* United States Patent 3,120,355 TRANSFER MECHANESM David Bowman, Wayne, Pa., assigner to l-T-E Circuit Breaker Corporation, Philadelphia, Pa., a corporation of Pennsylvania iled Ban. Z5, 1962, Ser. No. Ii68,679

6 Cian/ns. (Cl. 242--47.l2)

This invention relates to a transfer mechanism and more particularly to a simply constructed structure for transferring a length of cable between two members which are in respective relative motion.

Oftentimes, a continual length of cable (such as electrical conductors, rope, or similar flexible material) must be transferred between two members which are in respecive relative motion. A typical example being the transmission of certain electrical signals between the stationary platform and the rotating antenna pedestal of an antenna drive system. Such drives are frequently employed to position antennae to radiate (or receive) omnidirectional energy in radar, radio astronomy, or various communications systems. Although the main energy associated with such antenna systems is usually transmitted by a non-continuous type of rotary joint, there are oftentimes associated signals which may be transferred between the rotating members by a continuous length of cable. Such cables would typically include low frequency electrical power cables, coaxial cable, smaller size flexible waveguides, or an assembly of such individual conducting cables.

My invention permits such a continuous cable assembly to be easily transferred between the stationary and rotating members of a rotary joint assembly. Also, my invention permits other types of differential motion between the two transfer members. In addition, the transferred cable need. not necessarily be associated with electrical signals, but could be a pressure tube of a vacuum system, manila rope, steel cable, etc.

Numerous types of winch arrangements are presently known in the art to transfer cable between relatively moving members. However, most of these have limited practical usage because of; (l) intricate construction; (2) severe limi-tation as to the thickness of cable that can be accommodated; (3) the substantial degree of liexibility required of the transferred cable; and (4) the amount of relative movement that can be transferred between the movable members. My invention is an improvement over such previously known embodiments in that it is of extremely simple structure; will permit various cross-sections of cable to be transferred, including cable which is fairly rigid and permit a number of relative rotations between the transfer members.

Basically, my invention consists in draping the cable peripherfally about both of two coaxial differentially rotating drums. In my specific example, one drum is shown stationary to correspond to the antenna rotary joint application. A guiding element projects out from the region between .the two drums to intercouple the cable between the drum surfaces las the drums are `diiferentially rotated. This guiding element revolves about the common drum axis at a speed generally related to the length of cable being transferred, so as to continuously bear against the cable and maintain proper tensionl of the cable as it is transferred. As the drum rotates and the guiding element revolves -thereabout, a transfer of cable Mice is smoothly and continuously effected between the differentially rotating end drums.

The number of turns of relative rotation permitted by my invention is determined merely by cable size and the axial length of the differentially rotating drums. Thus, a system may be constructed to permit any number of limi-ted rotations between the end drums.

In previous cable transfer mechanisms, the cable .was completely wrapped about the guiding element. Consequently, only a fairly flexible cable of limited cross-section could be transferred without the use `of an excessively large guiding element. In my invention, the guiding element merely bears against the cable in the transferring region to exert constant tension. Since the cable is not completely wrapped .about this guiding element, cables of limited flexibility may be used in systems constructed in accordance with my invention.

There are two basic embodiments of my invention. In a 4first embodiment, the movement of the guiding element is determined by the differential rotation of the drums. Appropriate gearing is included between the guiding element and the drum members to effect the proper revolving of the guiding element. In a second embodiment of my invention the movement of the guiding element is determined primarily by the actual movement of this transferred cable, and not by the differential rotation of the drums. i

ln the illustrated systems of my iirst embodiment, both drums are aligned and of the same external diameter. One drum is stationary and the other is rotated about the common axis. The guiding element, shown as a pulley, is attached to a shaft having a shaft axis generally perpendicular to the common drum axis. The pulley end of the shaft extends out from the region between adjacent drum ends. The other end of the shaft extends diametrically across the adjacent drum ends and contains a set of gears. These gears are engaged by gear teeth circumferentially located about the adiacent ends of the differentially rotating drums. As one of Ithe drums is rotated, lthis gearing arrangement will cause the shaft and guiding element to move in the drum direction about the common drum axis, but at one-half the drum rotational speed. Should other drum 'diameter relationships, or other modes of differential drum rotation be desired, appropriate differential gearing arrangements well known in the art would be substituted.

ln a slight modification of this embodiment, the diametrically extending shaft containing the gears is replaced with a structure which will not obstruct signal passage through the central region of the differentially rotating drums. The gears are attached to stub shafts secured to diametrically opposite ends of an annular element which rotates about the drum axis.

ln my second embodiment the guiding element is biased against the cable to maintain proper tension; a spring bias arrangement being shown for illustrative purposes. The guiding element is secured to an annular member which freely rotates about the main axis of the differentially rotating drums. The spring urges the annular member against the cable, causing the guiding element to revolve about the main axis Ito take up the slack as the cable is transferred between the drums.

lt is, accordingly, a primary object of this invention E to transfer a length of cable between two relatively moving members.

Another object of the present invention is to provide a simplified structure to guide the transfer of a cable b..- tween two differentially rotating members.

A further object of the present invention is Ito provide a simplified cable transferring guide which moves at a speed related to the differential rotation of the cable ends.

Still another object of this invention is to provide a cable transfer mechanism between a stationary and rotating drum in which an external guide rotates therewith at a speed related to the length of cable to be transferred.

Still a further object of the present invention is to transfer cable between differentially rotating drum with a guiding element external to the drum that bears against the cable.

Yet another object of the present invention is to transfer a cable between two differentially rotating members whereby a biased guide maintains continuous tension against the transferred cable length.

These as well as other objects of the instant invention will readily become apparent after reading [the following description of the accompanying drawings in which:

FIGURE 1 is'a perspective view of a first embodiment of my invention.

FIGURE 2 is a side elevation of the embodiment of FIGURE 1.

FIGURE 3 is a plan View of the guiding element rotational mechanism of my first embodiment taken along line 3 3 of FIGURE 2 and looking in the direction of the arrows.

FIGURE 4 is a plan View of a slight modification of the embodiment shown in FIGURES 1 through 3.

FIGURE 5 is a perspective View of a second embodiment of my invention.

FIGURE 6 is a side elevation of the embodiment of FIGURE 5.

FIGURE 7 is a plan View of the guiding element rotational mechanism of my second embodiment taken along line 7-7 of FIGURE 6, and looking in the direction of the arrows.

Referring first to FIGURES 1 and 2, both drums 10 and 20 are illustratively shown as being of equal diameter. Lower drum 2d is secured to stationary shaft 12. Upper drum 10 is secured to shaft 13 of motor M Whereby it is rotated about main axis 1I, coaxial with drum 20.

A continuous length of cable 30 is wrapped about the peripheral regions of drums 1? and 2t). Cable 30 could be any flexible cable-like material such as coaxial signal cable, low frequency transmission wires, flexible Waveguide, rope, steel cable, vacuum pressure tubes, etc. Cable 30 is shown maintained about the peripheral region of the drums by frictional Contact. If necessary, appropriate grooving (not shown) could be added. Ends 31 and 32 of the cable are secured to the drum surfaces near the remote ends 14 and 24 of the drums, by brackets 33 and 34, respectively.

The adjacent end sections 15 and 25 of the drums contain a circumferential arrangement of gear teeth about their respective outer regions forming face gears 40 and 41. These face gears engage gears 42 and 43 shown as spur gears, with it being understood that a bevel or other gear arrangements could likewise be used. Gears 42 and 43 are attached by shaft 44 which extends diametrically across the adjacent ends (15 and 25) of the differentially rotating drums. The axis 16 of shaft 44 is preferably generally perpendicular to main axis 11. A guiding element 45, here shown as a pulley, is mounted to the end of shaft 44 extending out from between other adjacent drum end sections (15 and 25). The lengths of this shaft portion is kept to a minimum to maintain a nearly tan gential transfer of cable 30 to guide 45. The transferred length of cable 30 is wrapped about a portion of the outer peripherial region of guiding pulley 45. A grooved path 46 may bc provided to maintain cable 30 about guide 45.

It is significant to note that cable 30 is only partially wrapped about a complete revolution of guide path 46, permitting a fairly rigid cable to be transferred.

To illustrate the operation of my invention assume clockwise rotation of upper drum 10, corresponding to an amount equal to a circumferential length L of that drum. This will cause cable 30 to tend to unwrap a similar length L from about upper drum It?. The gearing arrangement between spur gears 42, 43 and face gears 4t), 41 will cause shaft 44 to rotate about axis 11 at a speed equal to onelialf the rotational speed of upper drum 10. This half speed relationship between shaft 44 and upper drum It) will cause guiding element 45 to revolve about main axis 11 in a clockwise direction, a circumferential distance corresponding to L/Z. This will compensate for one-half of the length of cable which tends to unwind from the periphery of upper drum 10. The remaining one-half length will be unwound from upper drum 10 and wound on lower drum 20 by transfer guide 45.

In many applications, particularly in rotary joints for microwave signal transmission, the inner region of the transferring drums (it) and 20) must be free from obstructions. To permit this, a slight modification, such as shown in FIGURE 4, may be made to remove the diametrically extending shaft 44 from the inner region of the drums. The diametrically extending single shaft 44 has been replaced with two individual stub shafts 47 and 48. Stub shafts 47 and 48 are attached to diametrically opposite portions of annular member 49.

This embodiment operates in the same manner as the above discussed FIGURES l through 3. As upper drum 10 is rotated, spur gears 42 and 43 engage face gears 40 and 41 causing annular member 49 to rotate about axis 11 at half the speed of upper drum 10. Guiding pulley 45, attached to stub shaft 48 will therefore be revolved about main axis 11 at the same half speed.

Although I show a 1:1 ratio of upper drum (10) and lower drum (2G) diameters, other arrangements may be constructed within the spirit and scope of my invention; it being understood that alternative differential gearing arrangement, well known in the art, would be employed to effect appropriate differential revolving of guiding element 45.

In the preferred embodiment of my invention, guiding element 45 is shown as a circular type pulley grooved to contain the transferred cable and rotatively maintained about shaft axis 16. Other configurations of guiding elements could be employed. However, the rotating pulley 45 is a preferable way of permitting the cable 30 to translate over such a guide member with a minimum of frictional engagement.

FIGURES 5 through 7 illustrate the second principal embodiment of my invention wherein the movement of guiding element 45 is determined primarily by the slack of the transferred length of cable 3d. Guiding element 45 is attached by stub shaft 50 to annular member 51. Ring bearing 52 is placed between the inner surface of annular member 51 and the innermost region 53 of drum 2t) to permit annular member S1 to rotate about main axis 11. Guiding element 45 attached thereto similarly revolves about that axis. Biasing spring 54 has one end 55 attached to the central region of the drum and its other end 56 attached to annular member 51. Spring 54 is so loaded so as to urge guiding element 45 to work against the tension exerted by cable 30. Stub shaft 57 extends upward to support drum 10, which is free to rotate about that shaft. Thus, as one of the drums will rotate so as to unwind cable 30, spring loaded guiding element 45 will be urged in a direction to take up the slack. Guiding element 45 in so moving will preferably cause one-half of the slack to be compensated for by being wound on the other drum, as discussed above in conjunction with my first embodiment. It is, of course, understood that other biasing arrangements may be substituted for spring 54 to effect the proper movement of guide 45.

inasmuch as the translation of guiding element is dctermined in this embodiment by the actual slack of the transferred length of cable, this embodiment may be used, as shown, with different drum diameters or with various ratios of differential drum rotation. Another advantage of this embodiment is that should lumps or other changes in the cross-section of the cable exist continuous tension of the cable will still be maintained.

Although l have described preferred embodiments of my novel invention, many variations and modifications will now be obvious to those skilled in the mt, and I prefer therefore to be limited not by the specific disclosure herein but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

l. A cable transfer mechanism comprising a first and a second member, each having a generally cylindrical cable receiving surface; said first and second members longitudinally positioned about a common axis, and having adjacently disposed generally circular end sections; said end sections having circumferentially disposed face gears; first drive means connected to at least one of said members to provide relative angular movement of said first and second surfaces about said common axis; a cable transfer guide pulley adjacent to said first and second cable receiving surfaces; said guide pulley being connected to a shaft and having a generally circular cable engaging path operatively positioned about the axis of said shaft; the portion of said path being engaged by a transferred cable at any one instant being less than a complete revolution of said guide pulley; said shaft axis being generally perpendicular to said common axis; said shaft being operatively connected to a second drive means; said second drive means including a planetary gear means positioned intermediate said end sections and mating with said face gears to revolve about said common axis at a speed related to the differential angular movement of said cable-receiving surfaces, thereby inducing corresponding differential movement of said pulley about said common axis; said first and second surfaces combinedly receiving a fixed predetermined length of cable; means fastening the ends of said fixed predetermined length of cable to said surfaces; said relative angular movement varying the distribution of said predetermined length of cable between said first and second surfaces, while being guided by the differentially induced movement of said guide pulley.

2. A cable transfer mechanism comprising a first and a second cable receiving drum; said drums being longitudinally positioned about a common axis; one of said drums being stationary; first drive means rotating the other of said drums about said common axis; said drums having adjacently disposed generally circular end sections; said end sections having circumferentially disposed face gears; a cable transfer guide pulley; said guide pulley being connected to a shaft and having a generally circular cable engaging path operatively positioned about the axis of said shaft; said shaft axis being generally perpendicular to said common axis; and said shaft being operatively connected to a second drive means; said second drive means including a planetary gear means positioned intermediate said end sections and mating with said face gears to revolve about said common axis at a speed less than said drum rotation; said first and second drums combinedly receiving a fixed predetermined length of cable; means fastening the ends of said fixed predetermined length of cable to said drums; said differential rotation varying the distribution of said predetermined length of cable between said first and second surfaces While being guided by the revolving of said guide pulley about said common axis.

3. A cable transfer mechanism comprising a first and a second cable receiving drum; first drive means connected to at least one of said drums to provide differential rotation of said drums about a common axis; said drums having adjacently disposed generally circular end sections; said end sections having circumferentially disposed face gears; a cable transfer guide pulley; said guide pulley being connected to a shaft means; said guide pulley having a generally circular cable engaging path operatively positioned about the axis of said shaft means; said shaft means being generally perpendicular to said common axis; planetary gears about said shaft means to operatively engage said drum end section face gears; said gearing engagement being operatively related to said differential drum rotation to revolve said guide pulley about said common axis responsive to said differential rotation of said drum, wherein said shaft means is comprised of a pair of diametrically extending stub shafts secured to an annular ring; each of said stub shafts being limited to the outer peripheral region of said end sections, thereby limiting the obstructions about the inner region of said drums.

4. A cable transfer mechanism comprising a first and a second member, each having a generally cylindrical cable receiving surface; said first and second members longitudinally positioned about a common axis, and having adjacently disposed generally circular end sections; said end sections having circumferentially disposed face gears; first drive means connected to at least one of said members to provide relative angular movement of said rst and second surfaces about said common axis; a cable transfer guide adjacent to said first and second cable receiving surfaces; said guide being connected to a shaft and having a cable engaging path operatively positioned about the axis of said shaft; said shaft axis being generally perpendicular to said common axis; said shaft being operatively connected to a second drive means; said second drive means including a planetary gear means positioned intermediate said end sections and mating with said face gears to revolve about said common axis at a speed related to the differential angular movement of said cable receiving surfaces thereby inducing corresponding differential movement of said guide about said axis; said first and second surfaces combinedly receiving a fixed predetermined length of cable; means fastening the ends of said fixed predetermined length of cable to said surfaces; said relative angular movement varying the distribution of said predetermined length of cable between said first and second surfaces, while being guided by the differentially induced movement of said guide.

5. A cable transfer mechanism comprising a first and a second member, each having a generally cylindrical cable receiving surface; said first and second members longitudinally positioned about a common axis, and having adjacently disposed generally circular end sections; said end sections having circumferentially disposed face gears; first drive means connected to at least one of said members to provide relative angular movement of said first and second surfaces about said common axis; a cable transfer guide adjacent to said first and second cable receiving surfaces; said guide being connected to a shaft and having a cable engaging path operatively positioned about the axis of said shaft; said shaft axis being generally perpendicular to said common axis; said shaft being operatively connected to a second drive means; said second drive means including a planetary gear means positioned intermediate said end sections and mating with said face gears to revolve about said common axis at a speed related to the differential angular movement of said cable receiving surfaces thereby inducing corresponding differential movement of said guide about said axis; said face gears and second drive means being confined to the outer peripheral regions of said end sections, thereby limiting the obstructions about the inner region of said members.

6. rThe cable transfer mechanism of claim 3, wherein said first and second drums combinedly receive a fixed predetermined length of cable, means fastening the ends of said fixed predetermined length of cable to said drums, said differential rotation varying the distribution of said predetermined length of cable between said first and second surfaces while being guided by the revolving of said guide pulley about said common axis.

References Cited in the le of this patent UNITED STATES PATENTS 2,755,916 Mcllvried et al. July 24, 1956 0 O 2,874,918 Steiber Feb. 24, 1959 FOREIGN PATENTS 555,522 Great Britain Aug. 26, 1943 IBM Technical Disclosure Bulletin. August 1960, pp. 49-50, 242/18A.

Volume 3, No. 3, 

1. A CABLE TRANSFER MECHANISM COMPRISING A FIRST AND A SECOND MEMBER, EACH HAVING A GENERALLY CYLINDRICAL CABLE RECEIVING SURFACE; SAID FIRST AND SECOND MEMBERS LONGITUDINALLY POSITIONED ABOUT A COMMON AXIS, AND HAVING ADJACENTLY DISPOSED GENERALLY CIRCULAR END SECTIONS; SAID END SECTIONS HAVING CIRCUMFERENTIALLY DISPOSED FACE GEARS; FIRST DRIVE MEANS CONNECTED TO AT LEAST ONE OF SAID MEMBERS TO PROVIDE RELATIVE ANGULAR MOVEMENT OF SAID FIRST AND SECOND SURFACES ABOUT SAID COMMON AXIS; A CABLE TRANSFER GUIDE PULLEY ADJACENT TO SAID FIRST AND SECOND CABLE RECEIVING SURFACES; SAID GUIDE PULLEY BEING CONNECTED TO A SHAFT AND HAVING A GENERALLY CIRCULAR CABLE ENGAGING PATH OPERATIVELY POSITIONED ABOUT THE AXIS OF SAID SHAFT; THE PORTION OF SAID PATH BEING ENGAGED BY A TRANSFERRED CABLE AT ANY ONE INSTANT BEING LESS THAN A COMPLETE REVOLUTION OF SAID GUIDE PULLEY; SAID SHAFT AXIS BEING GENERALLY PERPENDICULAR TO SAID COMMON AXIS; SAID SHAFT BEING OPERATIVELY CONNECTED TO A SECOND DRIVE MEANS; SAID SECOND DRIVE MEANS INCLUDING A PLANETARY GEAR MEANS POSITIONED INTERMEDIATE SAID END SECTIONS AND MATING WITH SAID FACE GEARS TO REVOLVE ABOUT SAID COMMON AXIS AT A SPEED RELATED TO THE DIFFERENTIAL ANGULAR MOVEMENT OF SAID CABLE-RECEIVING SURFACES, THEREBY INDUCING CORRESPONDING DIFFERENTIAL MOVEMENT OF SAID PULLEY ABOUT SAID COMMON AXIS; SAID FIRST AND SECOND SURFACES COMBINEDLY RECEIVING A FIXED PREDETERMINED LENGTH OF CABLE; MEANS FASTENING THE ENDS OF SAID FIXED PREDETERMINED LENGTH OF CABLE TO SAID SURFACES; SAID RELATIVE ANGULAR MOVEMENT VARYING THE DISTRIBUTION OF SAID PREDETERMINED LENGTH OF CABLE BETWEEN SAID FIRST AND SECOND SURFACES, WHILE BEING GUIDED BY THE DIFFERENTIALLY INDUCED MOVEMENT OF SAID GUIDE PULLEY. 